New and Exciting in PLoS Biology

Bioethics Grows Up:

When I taught my first course in bioethics to first-year students at Columbia University's College of Physicians and Surgeons in the spring semester of 1981, bioethics was still in its formative years. There were scant few textbooks around and even fewer anthologies, and I could not assume that any of my students had ever read anything by a bioethicist or about bioethics. The key institutions in the field at that time, the Hastings Center, then in Hastings-on-Hudson, New York, and the Kennedy Institute at Georgetown University in Washington, DC, were barely over a decade old, and only one journal devoted to bioethics had been publishing for a significant period of time. Most major medical and biomedical journals were wary of publishing pieces on ethics, because the editors did not think that articles on a soft and mushy subject such as ethics were appropriate for journals of medicine and science. An instructor in those days really had to scramble to find and assemble the best writings and be ready to incur a hefty Xeroxing bill.

Darwinian Evolution on a Chip:

The principles of Darwinian evolution are fundamental to understanding biological organization and have been applied to the development of functional molecules in the test tube. Laboratory evolution is greatly accelerated compared with natural evolution, but it usually requires substantial manipulation by the experimenter. Here we describe a system that relies on computer control and microfluidic chip technology to automate the directed evolution of functional molecules, subject to precisely defined parameters. We used a population of billions of RNA enzymes with RNA-joining activity, which were challenged to react in the presence of progressively lower concentrations of substrate. The enzymes that did react were amplified to produce progeny, which were challenged similarly. Whenever the population size reached a predetermined threshold, chip-based operations were executed to isolate a fraction of the population and mix it with fresh reagents. These steps were repeated automatically for 500 iterations of 10-fold exponential growth followed by 10-fold dilution. We observed evolution in real time as the population adapted to the imposed selection constraints and achieved progressively faster growth rates over time. Our microfluidic system allows us to perform Darwinian evolution experiments in much the same way that one would execute a computer program.

Rethinking Outreach: Teaching the Process of Science through Modeling:

There has been a recent call for undergraduate faculty to engage in "scientific teaching"--a way of active teaching that places equal emphasis on both the process of science and the facts of science [1]. We endorse this approach and believe that the Milwaukee School of Engineering (MSOE) SMART Team modeling program captures many of the principles of scientific teaching in a high school outreach program by exposing students to the "real world of science" as practiced in a local research lab. SMART Teams, which consist of a small group of high school students and their teacher, work with a local research lab to design and build a physical model of the protein that is the focus of the lab's research. During this modeling project, the students learn that science is much more than just the facts documented in their textbooks. They see that science is a process whereby real people--undergraduates, graduate students, post-docs, and principal investigators--go about learning something about a molecular world invisible to the naked eye. And in the molecular biosciences, what they are learning can be pretty amazing. While experiencing the culture of a research lab, SMART Team students begin to imagine themselves in the roles of their scientist mentors.

How Quickly Can a Rat Perceive Novel Odors?:

Odor perception in mammals is a multistep process that begins when olfactory sensory neurons in the animal's nose detect an odor molecule and then transmit that sensory information as an electrical signal to the brain. The first brain area to receive these signals is the olfactory bulb, where the sensory neurons end in small structures called glomeruli. Olfactory cues trigger complex patterns of activity both in the olfactory sensory neurons and in the glomeruli within the brain. How these complex patterns underlie an animal's ability to sense and respond to odors remains obscure. In a new study, Daniel Wesson et al. shed light on how these early signals lead to odor perception and subsequent behavioral changes by investigating how quickly a rat can respond to a novel odor. The speed of response, they show, depends on how quickly the olfactory bulb receives neural information about such an odor from the sensory neurons.